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pharm - OBG > Inflammatory Bowel Disease > Flashcards

Inflammatory Bowel Disease Flashcards

1
Q

What are the two main diseases that come under Inflammatory Bowel Disease?

A

Ulcerative Colitis

Crohn’s Disease

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2
Q

What is the underlying pathogenesis of these diseases based on?

A

It boils down to a defective interaction between the mucosal immune system and gut flora

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3
Q

What type of IBD is obesity a risk factor for?

A

Crohn’s Disease

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4
Q

Which T cell responses are involved in:

a. Ulcerative Colitis
b. Crohn’s Disease

A

a. Ulcerative Colitis
Th2

b. Crohn’s Disease
Th1

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5
Q

What are the main cytokines in:

a. Ulcerative Colitis
b. Crohn’s Disease

A

a. Ulcerative Colitis
IL-5
IL-13

b. Crohn’s Disease
TNF-alpha

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6
Q

Which layers of the gut are affected in:

a. Ulcerative Colitis
b. Crohn’s Disease

A

a. Ulcerative Colitis
Mucosa + Submucosa

b. Crohn’s Disease
All Layers

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7
Q

Describe which regions of the gut are affected in:

a. Ulcerative Colitis
b. Crohn’s Disease

A

a. Ulcerative Colitis
Starts at the rectum and proceeds proximally (continuous inflammation)

b. Crohn’s Disease
Can be anywhere on the GI tract (mouth to anus)
Patchy inflammation- cobblestone appearance

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8
Q

Are abscesses, fissures and fistulae common in:

a. Ulcerative Colitis
b. Crohn’s Disease

A

a. Ulcerative Colitis
No

b. Crohn’s Disease
Yes

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9
Q

Describe the effectiveness of surgery in:

a. Ulcerative
b. Crohn’s Disease

A

a. Ulcerative Colitis
Curative

b. Crohn’s Disease
Not always curative, even if the affected area is cut out, it often reoccurs

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10
Q

Describe some supportive therapies that are given for IBD

A

Nutritional therapy

Fluid/electrolytes

Potentially even blood transfusions/oral iron

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11
Q

What are the three types of classic symptomatic treatment for IBD?

A

Aminosalicylates

Glucocorticoids

Immunosuppressants

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12
Q

What is the main aminosalicylate drug?

A

Mesalazine

AKA 5-aminosalicylic acid (5-ASA)

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13
Q

What is a slightly more complex aminosalicylate?

A

Olsalazine (this is 2 linked 5-ASA’s)

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14
Q

What type of drug are aminosalicylates?

A

Anti-inflammatory

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15
Q

Describe the mechanism of anti-inflammatory action of aminosalicylates.

A

They inhibit IL-1, TNF-alpha and PAF (platelet activating factor)

Decrease antibody secretion

Reduced cell migration (macrophages)

Localised inhibition of immune responses

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16
Q

Describe the activation of aminosalicylates.

A

Mesalazine does not have to be activated any further

Olsalazine must be activated by colonic flora

17
Q

Describe the effectiveness of aminosalicylates in Ulcerative Colitis and Crohn’s Disease.

A

They are effective at inducing and maintaining remission in UC

They are better than steroids at inducing remission in UC

They are less effective in CD

18
Q

Describe the use of glucocorticoids in IBD.

A

Use of glucocorticoids in UC is in decline because aminosalicylates are better

Glucocorticoids are still the drug of choice for inducing remission in CD

However, side effects are likely if they are used to maintain remission

19
Q

Describe some strategies for minimising the side effects of glucocorticoids. (for use in IBD)

A

Topical administration (e.g. enemas and suppositories)

Low dose

Use oral or topically administered glucocorticoid with a high first pass metabolism

20
Q

What is an example of a glucocorticoid that has relatively few side effects?

A

Budesonide

21
Q

Describe the effectiveness of budesonide compared to other glucocorticoids.

A

Budesonide has fewer side effects than other glucocorticoids but it is less effective at inducing remission in CD

22
Q

State three immunosuppressive agents that could be used in IBD.

A

Azathioprine

Methotrexate

Cyclosporin – only useful in severe UC

23
Q

Describe the onset of action of azathioprine.

A

Slow onset – can take 3-4 months

24
Q

Describe the activation of azathioprine.

A

Azathioprine needs to be metabolised by gut flora to 6-mercaptopurine

25
Q

Describe the mechanism of action of azathioprine.

A

6-mercaptopurine is a purine antagonist

It interfered with DNA synthesis and cell replication

It impairs: 
 Cell- and antibody-mediated immune responses 
 Lymphocyte proliferation 
 Mononuclear cell infiltration 
 Synthesis of antibodies

It enhances:
 T cell apoptosis

26
Q

What are the unwanted effects of azathioprine?

A

Nearly 10% of patients stop treatment because of the side effects

Pancreatitis

Bone marrow suppression

Hepatotoxicity

Increased risk (4 fold) of lymphoma and skin cancer

27
Q

Describe the metabolism of azathioprine.

A

There are three routes of metabolism of azathioprine
 Route resulting in the production of beneficial active metabolites that also cause myelosuppression (HPRT pathway produces 6-TIMP –> 6-TGN)

 Route resulting in hepatotoxic metabolites with no beneficial effect (TPMT produces 6-MMP)

Xanthine Oxidase (XO) Pathway– produces inert metabolites (6-TU)

Xanthine oxidase is, fortunately, the main route of azathioprine metabolism - but this is inhibited by allopurinol (a drug for gout )

28
Q

In what clinical situation could there be a problem with azathioprine metabolism?

A

If the patient is taking allopurinol

Allopurinol is used to treat gout and is a xanthine oxidase inhibitor

This will result in the azathioprine being shunted down the hepatotoxic and myelosuppressive routes of metabolism

29
Q

What is the mechanism of action of Methotrexate?

A

Folate antagonist

It reduces the production of thymidine and other purines

NOTE: not widely used because of significant side effects

30
Q

What are the three potential mechanisms of manipulating the gutmicrobiome?

A

Nutrition based therapies – probiotics could be useful in UC, no evidence in CD

Faecal Microbiota Replacement Therapy (FMT) – could be useful in UC

Antibiotics – Rifaximin
 Interferes with bacterial transcription by binding to RNA polymerase
 Induces and sustains remission in moderate CD
 Potentially beneficial in UC

31
Q

Give 2 examples of anti-TNF-alpha antibodies.

A

Infliximab (IV)

Adalimumab (SC)

32
Q

Describe the effectiveness of anti-TNF- antibodies in Crohn’s Disease.

A

60% of patients will respond within 6 weeks are it is potentially curative

33
Q

Describe the mechanism of action of anti-TNF-alpha antibodies.

A

Knocking out TNF-alpha leads to general downregulation of other inflammatory cytokines

Reduced infiltration and activation of leukocytes

Induced cytolysis of cells expressing TNF-alpha

Promotes apoptosis of activated T cells

34
Q

Describe the pharmacokinetics of anti-TNF-alpha antibodies.

A

Given intravenously
Long half-life – 9.5 days

Most patients relapse between 8-12 weeks

Repeat infusion given after 8 weeks

35
Q

What is a problem with anti-TNA-alpha therapy that may require changes in the treatment guidelines?

A

Evidence showed up to 50% of responders stopped responding after 3 years

This is due to production of anti-drug antibodies and increased drug clearance

36
Q

What are the adverse effects of anti-TNA-alpha therapy?

A

Increased risk of tuberculosis or Risk of reactivating dormant TB

Increased risk of septicaemia

Worsening heart failure

Increased risk of demyelinating disease

Increased risk of malignancy

Can be immunogenic

37
Q

What were the key findings from the SONIC trial?

A

Early use of infliximab is better than last resort use in patients with refractory disease

CRP levels and endoscopy may allow identification of patients that are most likely to benefit

There is a greater risk of infection and lymphoma

pharm - OBG (25 decks)

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